Glue application method for cold seal cohesive packaging

ABSTRACT

A method for applying a cold seal adhesive is disclosed. The method includes the steps of delivering a cold seal adhesive to a nip between a rotating metering roller and an adjacent rotating transfer roller having a transfer surface, transferring a quantity of adhesive to the transfer surface, rotating the transfer roller whereby the transfer surface contacts a printing die mounted to a rotating die roller disposed adjacent to the transfer roller, rotating the die roller whereby the printing die contacts the at least one adhesive region on the interior surface of the housing and transfers at least a second portion of the quantity of adhesive from the printing die to the at least one adhesive region forming a film as the housing advances between the die roller and the impression roller, the film having a thickness between 0.0015-0.007 inches, and drying the adhesive on the housing.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.13/692,728 filed on Dec. 3, 2012 which is related to, and claims thepriority benefit of, U.S. Provisional Application Nos. 61/636,210 filedon Apr. 20, 2012, 61/636,226 filed on Apr. 20, 2012, and 61/636,233filed on Apr. 20, 2012, the entire contents of which are incorporatedherein by reference.

BACKGROUND

Conventional packaging for the retail sale of consumer products hasevolved to include display packs that not only allow unobstructedviewing of a product without opening the packaging, but also preventtampering with the product, deter theft of the product, and limitretailer costs of an unsaleable product due to damage to the packaging.Among the types of consumer packaging developed to address these needsis a clear plastic blister pack in combination with a cardboard,corrugated fiberboard, or paperboard frame that encloses the outer edgesof the blister pack. The product is enclosed inside the blister pack,and the combination of the blister pack and the corrugated frameprevents easy access to the product. This type of packaging deters theftby providing a bulky package, and it also provides a protective shieldto the enclosed product while still allowing a .consumer to view theproduct.

Traditionally, the corrugated frame used in combination with plasticblister pack is made up of two sheets of material adhered together withan adhesive, such as a hot melt glue, a heat-sensitive adhesive, or acohesive contact adhesive. However, these adhesives and their respectiveapplication processes have several disadvantages. For instance, hot meltglues are typically difficult to apply in a controlled fashion, and thequality of the resulting seal varies accordingly. Heat-sensitiveadhesives often provide ineffective seals when used with corrugatedsubstrates because the corrugated sheets are poor heat conductors. Suchadhesives are also difficult to use in a high volume manufacturingprocess where corrugated frames must be stacked in an efficient mannerbecause the adhesive is slow to dry and is also susceptible to smearingwhen coining into contact with another surface. Furthermore, as thecorrugated frames are stacked higher and higher, the accumulation ofweight in the stack increases the possibility of the frames adhering toeach other once the adhesive has been applied. Finally, conventionalcohesive contact adhesives also suffer from these and other drawbacks inthat they are applied over the entire interior surface of the corrugatedpackaging, creating waste, slowing the production process, andinevitably leaving an undesirable adhesive residue on the plasticblister pack, which impacts the recyclability of the blister pack whenseparated from the corrugated frame.

The abovementioned conventional adhesives create excess waste bothduring the manufacturing process and once the product is removed fromthe packaging by a consumer. In recent years, there has also been anincreased awareness of the environmental impact from the manufacture,use and disposal of product packaging. While both the plastic blisterpack and corrugated frame used in conventional packaging are separatelyrecyclable, the adhesive is not and, thus, can impact the recyclabilityof the rest of the packaging. It is therefore desirable to use anadhesive that causes a minimal environmental impact when disposed.

Accordingly, a need exists for a method of efficiently applying anadhesive for product packaging at high production rates that enables acombination plastic blister pack and corrugated product packagingcontainer that is cost-effective to produce, environmentally friendly tomanufacture and dispose, and sufficiently protects a product duringshipping, handling, and display.

SUMMARY

According to one aspect of the present disclosure, a method of applyinga cold seal cohesive for product packaging is disclosed, the methodincluding the steps of delivering a cold seal adhesive to a nip betweena rotating metering roller and an adjacent rotating transfer rollerhaving a transfer surface; transferring a quantity of adhesive is to thetransfer surface; rotating the transfer roller whereby the transfersurface contacts a printing die mounted to a rotating die rollerdisposed adjacent the transfer roller, whereby at least a first portionof the quantity of adhesive is transferred from the transfer surface tothe printing die; feeding a housing between the die roller and anadjacent rotating impression roller, wherein the housing comprises aninterior surface, an opposing exterior surface, a top portion, a bottomportion, and at least one adhesive region on the interior surface, andwherein the impression roller is capable of supporting the exteriorsurface of the housing, whereby simultaneous rotation of the die rollerand the impression roller advances the housing therebetween; rotatingthe die roller whereby the printing die contacts the at least oneadhesive region on the interior surface of the housing and transfers atleast a second portion of the quantity of adhesive from the printing dieto the at least one adhesive region as the housing advances between thedie roller and the impression roller; and drying the adhesive on thehousing, wherein the adhesive is a latex-based adhesive, with aviscosity of no more than 450 centipoise, which adheres to the housingwhen applied in a liquid form but is capable of drying such that thedried adhesive lacks tackiness and is cohesive only to itself whencompressed with a pressure.

In at least one embodiment of the present disclosure, the transferroller further includes a plurality of cells engraved into the transfersurface of the transfer roller, the cells being capable of accepting thequantity of the adhesive from the nip, wherein the cells contact theprinting die mounted to the rotating die roller disposed adjacent thetransfer roller, whereby the adhesive is transferred from the cells tothe printing die. In at least one embodiment of the present disclosure,the housing is capable of a folded configuration whereby the interiorsurface of the top portion at least partially contacts the interiorsurface of the bottom portion.

In at least one embodiment of the present disclosure, the method furtherincludes the steps of folding the housing having a cold seal adhesiveapplied thereon into the folded configuration; and applying at least10,000 pounds per square inch of pressure to at least a portion of theexterior surface of the housing opposite the adhesive region when thehousing is in the folded configuration. In at least one embodiment ofthe present disclosure, the adhesive is delivered to the nip using aperistaltic pump. In at least one embodiment of the present disclosure,the adhesive is dried on the housing using one or more dryers and isadvanced to the one or more dryers by a plurality of feed rollers. In atleast one embodiment of the present disclosure, the one or more dryersis selected from a group consisting of radio-wave dryers, macro-wavedryers, and infrared dryers.

In at least one embodiment of the present disclosure, a method forapplying a cold seal adhesive includes the steps of delivering a coldseal adhesive to a volume within a chambered doctor blade disposedadjacent a rotating transfer roller having a transfer surface;transferring a quantity of adhesive is to the transfer surface from thevolume of the chambered doctor blade; rotating the transfer rollerwhereby the transfer surface contacts a printing die mounted to arotating die roller disposed adjacent the transfer roller, whereby atleast a first portion of the quantity of adhesive is transferred fromthe transfer surface to the printing die; feeding a housing between thedie roller and an adjacent rotating impression roller, wherein thehousing comprises an interior surface, an opposing exterior surface, atop portion, a bottom portion, and at least one adhesive region on theinterior surface, and wherein the impression roller is capable ofsupporting the exterior surface of the housing, whereby simultaneousrotation of the die roller and the impression roller advances thehousing therebetween; rotating the die roller whereby the printing diecontacts the at least one adhesive region on the interior surface of thehousing and transfers a second portion of the quantity of adhesive fromthe printing die to the at least one adhesive region as the housingadvances between the die roller and the impression roller; and dryingthe adhesive on the housing, wherein the adhesive is a latex-basedadhesive, with a viscosity of no more than 450 centipoise, which adheresto the housing when applied in a liquid form but is capable of dryingsuch that the dried adhesive lacks tackiness and is cohesive only toitself when compressed with a pressure.

In at least one embodiment of the present disclosure, a method forsealing product packaging using a cold seal adhesive includes the stepsof applying a cold seal adhesive within at least one adhesive region onan interior surface of a housing, the housing further comprising anexterior surface opposite the interior surface, a top portion, a bottomportion, a perimeter, and at least one adhesive region on the interiorsurface; folding the housing into a folded configuration, wherein thefolded configuration comprises the interior surface of the top portionat least partially contacting and the interior surface of the bottomportion; and applying at least 10,000 pounds per square inch of pressureto the exterior surface of the housing opposite the at least oneadhesive region when the housing is in the folded configuration, therebysealing the housing, wherein the adhesive is a latex-based adhesive,with a viscosity of no more than 450 centipoise, which adheres to thehousing when applied in liquid form, is capable of drying such that thedried adhesive lacks tackiness, and is cohesive only to itself whencompressed with a pressure of at least 10,000 pounds per square inch.

In at least one embodiment of the present disclosure, the step ofapplying pressure is enabled by a cold seal compressor that includes aplurality of sealing roller pairs mechanically connected to a rotatabledrive spline, the drive spline being mechanically coupled to a motor,whereby the motor powers rotation of the drive spline, wherein eachsealing roller pair is capable of advancing the housing between eachsealing roller pair while applying a sealing pressure between 10,000 and40,000 pounds per square inch therebetween. In at least one embodimentof the present disclosure, the plurality of sealing roller pairs eachinclude at least one upper sealing roller mounted on a rotatable upperroller shaft, the upper roller shaft supported by at least one upperbearing disposed adjacent the upper sealing roller; and at least oneopposing lower sealing roller mounted on a rotatable lower roller shaft,the lower roller shaft supported by at least one lower bearing disposedadjacent the lower sealing roller, wherein the at least one lowersealing roller is disposed adjacent the at least one upper sealingroller.

In at least one embodiment of the present disclosure, the plurality ofsealing roller pairs each further include at least one upper geardisposed on the upper roller shaft adjacent the at least one upperbearing; and at least one lower gear disposed on the lower roller shaftadjacent the at least one lower bearing, wherein the at least one uppergear is mechanically coupled to a corresponding at least one lower gearand the at least one lower gear is mechanically coupled to the drivespline. In at least one embodiment of the present disclosure, theplurality of sealing roller pairs each further include at least oneguard covering each of the at least one upper sealing roller and the atleast one lower, sealing roller, the guard configured to prevent anoperator from inserting a finger, clothing, or other item between therotating sealing roller pairs or gears.

In at least one embodiment of the present disclosure, at least two ofthe plurality of sealing roller pairs are positioned on the same planeand separated by a distance less than a width of the housing, wherebythe housing is sealed along at least two sides of the perimeter of thehousing. In at least one embodiment of the present disclosure, guidesalign the housing with the at least two sealing roller pairs as thehousing is advanced therebetween. In at least one embodiment of thepresent disclosure, at least one pair of the plurality of sealing rollerpairs is mounted to a platform capable of translating along the drivespline, whereby the distance separating at least two of the plurality ofsealing roller pairs is adjustable. In at least one embodiment of thepresent disclosure, at least two of the plurality of sealing rollerpairs are positioned on the same plane and perpendicular to at least twoother pairs of the plurality of sealing roller pairs.

BRIEF DESCRIPTION OF THE DRAWINGS

The described embodiments and other features, advantages and disclosurescontained herein, and the manner of attaining them, will become apparentand the present disclosure will be better understood by reference to thefollowing description of various exemplary embodiments of the presentdisclosure taken in conjunction with the accompanying drawings, wherein:

FIG. 1 shows a cold seal product packaging container according to thepresent disclosure;

FIG. 2 shows a housing for a product packaging container according tothe present disclosure;

FIG. 3 shows a housing for a product packaging container according tothe present disclosure;

FIG. 4 shows a cross-sectional view of a housing for a product packagingcontainer according to the present disclosure, taken across line IV-IVof FIG. 2;

FIG. 5 shows a cross-sectional view of a housing for a product packagingcontainer according to the present disclosure, taken across line V-V ofFIG. 1;

FIG. 6 shows a housing web for a product packaging container accordingto the present disclosure;

FIG. 7 shows a perspective view of an adhesive application apparatus foran adhesive application method according to the present disclosure;

FIG. 8 shows a side view of an adhesive application apparatus for anadhesive application method according to the present disclosure;

FIG. 9 shows a detail view taken from FIG. 8 of an adhesive applicationapparatus for an adhesive application method according to the presentdisclosure;

FIG. 10 shows a pump for an adhesive application apparatus for anadhesive application method according to the present disclosure;

FIG. 11 shows a perspective view of a cold seal compressor for anadhesive application method according to the present disclosure;

FIG. 12 shows a plan view of a cold seal compressor for an adhesiveapplication method according to the present disclosure;

FIG. 13 shows a detail view of a cold seal compressor for an adhesiveapplication method according to the present disclosure;

FIG. 14 shows a plan view of a cold seal compressor for an adhesiveapplication method according to the present disclosure;

FIG. 15 shows a side view of a cold seal compressor for an adhesiveapplication method according to the present disclosure;

FIG. 16 shows a front view of a cold seal compressor for an adhesiveapplication method according to the present disclosure;

FIG. 17 shows an adhesive application method according to the presentdisclosure;

FIG. 18 shows a cold seal compressor method according to the presentdisclosure;

FIG. 19 shows a side view of an alternative adhesive applicationapparatus for an adhesive application method according to the presentdisclosure;

FIG. 20 shows a perspective view of an alternative adhesive applicationapparatus for an adhesive application method according to the presentdisclosure;

FIG. 21 shows a detail view taken from FIG. 19 of an adhesiveapplication apparatus for an adhesive application method according tothe present disclosure;

FIG. 22 shows an alternative adhesive application method according tothe present disclosure.

Like reference numerals indicate the same or similar parts throughoutthe several figures.

An overview of the features, functions and configuration of thecomponents depicted in the various figures will now be presented. Itshould be appreciated that not all of the features of the components ofthe figures are necessarily described. Some of these non-discussedfeatures, such as various couplers, etc., as well as discussed featuresare inherent from the figures. Other non-discussed features may beinherent in component geometry or configuration.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of this disclosure is thereby intended.

The disclosure of the present application provides a cold seal productpackaging container and a method of making the same. A cold seal productpackaging container may be constructed of a plastic blister pack and acorrugated fiberboard enclosure and employing a unique cold sealadhesive and adhesive application process, which results in a containerthat is strong, tamper-proof and recyclable and can be manufactured at amuch faster rate than conventional product packaging. Though the productpackaging container may be commonly used with retail consumer products,it will be appreciated that the product packaging container is notlimited to use with these specific types of products or distributionoutlets and, consequently, may be used to package any article. Likewise,though the adhesive application process is described relative to aproduct packaging container, it will be appreciated that the adhesiveapplication process is not limited to the specific product packagingcontainer used to illustrate the process.

FIG. 1 shows a cold seal product packaging container according to thepresent disclosure. As shown in FIG. 1, the product packaging container10 includes a housing 20, which encloses and retains a product tray 30and is sealed together with a cold seal adhesive 40. The container 10 isconfigured to enclose one or more articles (not shown), such as consumerproducts, within the tray 30 and to protect products from damage,blemish, or theft. To adequately protect the product, the adhesive 40must seal the housing 20 around the edges of tray 30 with sufficientstrength and durability to securely support the products' weight duringshipping, handling, and display of the product and to discouragetampering with the container 10 and its contents. In FIG. 1, housing 20is shown in a folded configuration as a part of the container 10, whichis the final configuration once container 10 has been fully formed andsealed as described more fully herein.

Referring to FIGS. 2-3, housing 20 is initially manufactured in anunfolded configuration prior to assembly into the container 10 ofFIG. 1. As shown in FIG. 3, the housing 20 includes an exterior surface23 and an opposing interior surface 25 and is bounded by a leading edge22, trailing edge 24, a first side edge 26, and second side edge 28.Further, the housing 20 is capable of being folded at a perforated lineof weakness 21 located substantially equidistant from leading edge 22and trailing edge 24. The line of weakness 21 defines a top portion 27and a bottom portion 29, which contact one another at the interiorsurface 25 when the housing 20 is in the folded configuration.

According to at least one embodiment of a product packaging containeraccording to the present disclosure, the housing 20 may include at leastone opening 36 formed through the exterior and/or interior surfaces 23,25. As shown in FIG. 1, the opening 36 may be formed to accept the tray30, whereby a suitable opening shape is formed as disclosed in moredetail herein. Though the opening 36 is depicted as being formed throughthe top portion 27, the housing 20 may include one or more additionalopenings 36 formed in either the top portion 27 and/or the bottomportion 29. Further, the exterior surface 23 may include graphic indicia39 identifying or advertising the product contained within container 10,displaying regulatory nutrition information, a universal product code ormatrix barcode, or any other information relevant to the product. Theindicia 39 may be printed on the exterior surface 23 by any suitableprocess or may be applied as a label to the exterior surface 23.

The housing 20 may be formed of corrugated fiberboard, such as E flutecorrugated fiberboard, paperboard, cardboard, chipboard, corrugatedplastic board, or any planar material suitable for the requirements of aproduct packaging container 10 as disclosed herein. The packagingcontainer 10 may also be made using numerous other substrates forhousing 20, such as 32 ECT E-flute, 32 ECT B-Flute, 200 lb test B-flute,and various microflutes (N&F), etc. Embodiments described herein we arenot limited to corrugated cardboard, as conventional packages usecorrugated cardboard for both “sheets” of their housing. Embodimentsdescribed herein may use virtually any paperboard substrate in anycombination. For example, embodiments may use an E-flute backer cardwith a SBS or chipboard front card to form a housing 20 for packagecontainer 10. Approximately 20% of the marketplace usescorrugated/corrugated sheet combinations, whereas the remaining 80% ofthe marketplace uses either chipboard/SBS or some combination ofchipboard/SBS and corrugated. Embodiments described herein may be usedwith more varieties of materials than conventional packaging provides.Though the housing 20 is shown with a rectangular shape, the perimeterof the housing 20 could form any desired shape and size.

In at least one embodiment of a product packaging container according tothe present disclosure, the tray 30 includes a blister portion 32 and aflange portion 34 as shown in FIG. 5. The blister portion 32 is formedto define a product volume 37 and a blister perimeter 33 appropriatelysized to accept and conform to a specific product to be packaged withinthe container 10. The flange portion 34 extends in a plane from theblister perimeter 33 and defines a flange perimeter 35. The flangeportion 34 enables the tray 30 to be trapped between the top portion 27and bottom portion 29 when the housing 20 is in the folded configurationwhile further enabling the blister portion 32 to project through theopening 36. In at least one embodiment of the present disclosure asshown in FIGS. 1 and 5, the opening 36 in housing 20 is formed to be thesame as or slightly larger than the blister perimeter 33 butsubstantially smaller than the flange perimeter 35, further enablingsecure handling and display of the product within container 10. Itshould be noted that the width of the flange portion 34 may vary withthe size and weight of the product to be secured within the container10. Larger and heavier products may generally require a wider flangeportion 34 to adequately distribute the weight of the product to thehousing 20 and to securely retain the flange portion 34 between the topportion 27 and bottom portion 29 in the folded configuration.

The tray 30 may be made of any material suitable for secure shipping,handling, and display of the product within the container 10. Exemplarymaterials may include clear plastic materials, such as polyethyleneterephthalate, that can be molded or thermoformed into a shape generallyconforming to the product to be secured within the container 10.

As mentioned above, adhesive 40 binds top portion 27 and bottom portion29 and seals product tray 30 within product packaging container 10.Adhesive 40 is a quick-drying, latex-based adhesive that, once dried,creates a no-tack surface and adheres only to other surfaces coated withthe same adhesive when placed under high pressure. In the embodimentshown in FIG. 3, adhesive 40 may be applied to interior surface 25within upper adhesive region 42, lower adhesive region 43, upper productadhesive region 44, and the lower product adhesive region 45. Whenhousing 20 is folded at weakness 21 and sufficient pressure is appliedto the housing 20, the adhesive 40 in the upper adhesive region 42 bondswith the adhesive 40 in the lower adhesive region 43, and the adhesive40 in the upper product adhesive region 44 bonds with the adhesive 40 inthe lower product adhesive region 45. The secure bonding of theseregions occurs only when sufficient pressure of at least 10,000 poundsper square inch (psi) is applied to the adhesive by a cold sealcompressor or other sealing device.

The cold seal adhesive 40 is specially formulated to provide thecharacteristics described herein. The cold seal adhesive 40 is anemulsion of natural and/or synthetic latex rubber in aqueous solution ofammoniated water with a solids content between 15 and 65 percent byweight. The viscosity of the cold seal adhesive 40 may be between 10 and450 centipoise (cP) at 20 revolutions per minute and 23 degrees Celsius(° C.) per ASTM D1084 Test Method B. Further, the density of cold sealadhesive 40 may be between 8.0 and 9.0 pounds per gallon (lb/gal) at 25°C., and the basicity or pH may be between 9.5 and 12 pH. The compositionof cold seal adhesive 40 may contain dispersants, surfactants,tackifiers, isocyanates, stabilizers, and antifoaming agents, as is wellknown in the art, without deviating from the scope of the disclosure. Inat least one embodiment of the present disclosure, cold seal adhesive 40has the following properties: the solids content is 57.5 percent byweight, the viscosity is 75 cP at 25° C., the density is 8.3 lb/gal, andthe pH is 10.0. In at least one embodiment of the present disclosure,the adhesive 40 has a solids content between 45 and 58 percent byweight, a viscosity between 75 and 200 cP at 23° C., a density between8.3 and 8.7 lb/gal at ° C., and a basicity between 10 and 11 pH.Viscosity may be measured using ASTM D1084 Test Method B using aBrookfield viscometer or ASTM D1084 Method D using Zahn Cups.

Being a latex-based adhesive, the viscosity of the cold seal adhesive 40increases dramatically under processing conditions that induce shearstress in the adhesive, causing shear thickening or agglomeration.Likewise, the cold seal adhesive 40 exhibits high shear viscosity, whichis a measure of resistance to flow at the high shear rates imposed bythe application process. However, to reduce shear sensitivity, the coldseal adhesive 40 has significantly lower viscosity and solids contentthan conventional cohesive adhesives used in the product packaging art.Further, the low viscosity and solid content enable the cold sealadhesive 40 to be applied and effective at a Film thickness between0.007-0.002 inches (in.) and typically 0.0015 in. Nonetheless, variousprocessing issues must be overcome to prevent inducing shear stress inthe adhesive and achieve the noted film thickness range duringapplication at high production rates.

Because adhesive 40 dries quickly and is only applied to the interiorsurface 25 of housing 20, the use of adhesive 40 allows multiplehousings to be stacked on top of one another during the manufacturingprocess, as the exterior surface 23 of one housing will not adhere tothe interior surface 25 of another housing. The ability to immediatelystack multiple housings 20 after application of adhesive 40 greatlyimproves the efficiency of the manufacturing process compared to priorart processes using conventional adhesives in which the adhesives wereslow to dry and were susceptible to smearing when coming into contactwith the other surfaces. Prior art manufacturing processes were alsolimited in the number of housings that could be stacked together, aseach accumulation of weight in a stack of housings increased thepossibility of the housings adhering to each other. Often housings aretransported standing on end instead of lying flat to avoid adhering thehousings together (commonly referred to as “blocking”); however, thehousings are susceptible to damage when transported this way. Unlikeconventional packaging using contact adhesives, housings 20 produced bythe adhesive application method of the present disclosure may behandled, stacked, stored, and transported in economically efficientquantities without sticking together because of the rapid drying processand the lack of tack achieved of the dried adhesive 40. The propertiesand application method of adhesive 40 also enable the adhesive 40 to beapplied prior to cutting housing 20, as an entire sheet of housings 200,as shown in FIG. 6 could pass through the machinery without adhesive 40smearing or leaving residue on the machinery.

As mentioned above, in at least one embodiment of a product packagingcontainer according to the present disclosure, the adhesive 40 may beapplied in specific adhesive regions on the interior surface 25 of thehousing 20. As depicted in FIGS. 3 and 4, the adhesive 40 may be appliedalong a perimeter of the housing 20 within an upper adhesive region 42and a lower adhesive region 43 that extend along each of the leading,trailing, first and second side edges 22, 24, 26, 28 and the line ofweakness 21, whereby the upper adhesive region 42 on the top portion 27substantially contacts the lower adhesive region 43 on the bottomportion 29 when the housing 20 is in the folded configuration. Becausethe adhesive will only adhere to itself under high pressure, anyadhesive region located on the top portion 27 of housing 20 should havea corresponding adhesive region on the bottom portion 29. As shown inFIG. 4, the perimeter adhesive region 42 may extend from the an edge 22,24, 26, 28 toward the center of the interior surface 25 but may notextend as far as the opening 36 as to avoid contact between the adhesive40 and the tray 30. In at least one embodiment of the presentdisclosure, the width of the upper and lower adhesive regions 42, 43extend no more than 12.9 millimeters (0.5 inches) toward the center ofthe interior surface 25. Applying the adhesive 40 in the narrowperimeter upper and lower adhesive regions 42, 43 prevents any contactbetween the adhesive 40 and the tray 30, which facilitates recyclabilityof the container 10 by enabling easy separation of the tray 30 from thehousing 20 without leaving contaminating adhesive 40 on the tray 30.

Alternatively, as shown in FIG. 3, a product packaging container 10 mayinclude an upper product adhesive region 44 and a lower product adhesiveregion 45 or any number of other adhesive regions separated from theperimeter adhesive regions 42, 43 by a region without adhesive 40.Regardless, to facilitate recyclability of container 10, the upper andlower product adhesive regions 44, 45 should be located so as not tocontact the tray 30.

In addition to facilitating recyclability of container 10, the totalarea of the interior surface 25 occupied by the perimeter adhesiveregion 42 may be reduced to minimize the amount of adhesive 40 includedin the container 10. Minimizing the adhesive region 42 reduces the costof container 10 by both reducing the amount of materials used andincreasing the rate of production of the housing 20. Nonetheless, asuffice amount of adhesive 40 must be used to ensure the top and bottomportions 27, 29 of housing 20 are sealed together with sufficientstrength and durability as required for a specific container 10 asdisclosed herein.

Traditionally, high speed printing press processes, for example,flexographic printing, are anticipated to induce shear stresses in amaterial used for printing, generally inks, on a substrate. Because inksare not generally adversely affected by the levels of shear stressinduced by conventional processes, operators have not had a need tomodify their high speed printing press processes to reduce the shearstresses induced. However, some adhesive materials, such as the coldseal adhesive 40, are sensitive to shear as described above.Consequently, conventional high speed printing processes are not capableof applying the cold seal adhesive 40 without inducing the shear stressresponsible for agglomeration of the adhesive. As a result, variousmodifications must be made to a conventional flexographic printing pressto enable continuous, high speed application of the cold seal adhesive40, as disclosed herein. With proper application, the cold seal adhesive40 enables production rates not possible using conventional packagingadhesives. For example, the cold seal adhesive 40 may be applied at aproduction rate of 3,300 feet per minute (ft/min), compared to 45 ft/minfor conventional application processes and adhesives. Further, the coldseal adhesive 40 may be applied prior to a die cutting operation, unlikeconventional adhesives, thereby allowing the die cutting operation to beincluded within the application process and providing additionalproduction efficiencies.

Adhesive 40 may be applied to housing 20 by a modified flexographicprinting process that uses a flexible relief die to control applicationof and minimize induced shear stress in the adhesive 40. The process mayinclude using a set of cylindrical rollers, positioned adjacent to eachother, which rotate relative to one another and are capable of metering,transferring and printing adhesive 40 on housing 20. Those of ordinaryskill in the art may recognize other machinery to effectively apply theadhesive. Once the adhesive 40 has quickly dried, the adhesive regionsin the top portion 27 and bottom portion 29 will only bond to each otherupon the application of high pressure from a cold seal compressor orother sealing device. Since the adhesive 40 is only applied to a limitednumber of adhesive regions, only those regions need to be sealed ratherthan the entire surface as in prior art packaging. This highlycontrolled application process not only reduces the amount of adhesive40 needed for the final container 10, but also allows the adhesive 40 tobe applied so that it is not in direct proximity to the product beingpackaged or the product tray 30.

FIG. 7 shows an apparatus for applying the adhesive for productpackaging according to the present disclosure. As shown in FIG. 7,adhesive application apparatus 100 includes a set of cylindrical rollers102, which are positioned adjacent one another, rotate relative to oneanother around their respective axes, and are thereby capable ofmetering, transferring, and printing the adhesive 40 on a substrate,such as housing 20. The adhesive application apparatus 100 resembles aconventional in-line flexographic printing machine commonly used toprint ink on packaging materials, such as housing 20. However, due tothe shear sensitivity of adhesive 40, a conventional in-lineflexographic printing machine is not capable of continuously applyingadhesive 40 effectively or efficiently. As a latex-based adhesive, theviscosity of the adhesive 40 increases dramatically under high-shearconditions due to shear thickening or agglomeration. Essentially, theadhesive 40 is activated by shear stress and will begin to crosslink,congeal, and agglomerate due to shear stress induced in the adhesive 40by the application process. Concurrently, conventional high speedapplication processes, such as flexographic printing, are disposed toinducing significant shear stress in an adhesive. Consequently, theadhesive application apparatus 100 differs in many respects from aconventional in-line flexographic printing machine, as described below,and therefore enables the adhesive application apparatus 100 to applythe adhesive 40 discretely within the top and bottom adhesive regions42, 43.

As shown in FIG. 7, the set of cylindrical rollers 102 may include ametering roller 110 disposed adjacent a transfer roller 120. The set ofcylindrical rollers 102 may further include a die roller 130 adjacentthe transfer roller 120, which is capable of applying a controlledamount of adhesive 40 onto a printing die 132 mounted on the die roller130. An impression roller 140 may be positioned adjacent the die roller130 and separated at a distance that permits the housing 20 to passtherebetween, thus enabling the printing die 132 to contact the interiorsurface 25 and imprint the adhesive 40 within the perimeter adhesiveregions 42, 43 while the impression roller 140 contacts and supports theexterior surface 23.

As shown in FIG. 8, the metering roller 110 is positioned adjacent tothe transfer roller 120 such that a nip gap 112 separates the outersurfaces of the metering roller 110 and the transfer roller 120. Thepurpose of the metering roller 110 is to control the amount of adhesive40 carried by the transfer roller 120 to the printing die 132 and, tothat extent, may be analogous to that of a doctor blade used in aconventional flexographic printing process. Accordingly, the adhesive 40is dispensed into the nip gap 112 from a dispense nozzle 155, as shownin FIG. 7. The nip gap 112 is set such that it enables an amount ofadhesive 40 to pool or puddle between the metering 110 and the transfer120 rollers. The pool of adhesive 40 formed between the metering 110 andthe transfer 120 rollers is commonly referred to as a nip 158. However,due to the shear sensitivity of the adhesive 40, the nip gap 112 must beset to ensure that shear forces do not cause the adhesive to polymerizeand congeal into a film on the metering 110 and the transfer 120rollers.

The purpose of the transfer roller 120, which may be commonly referredto as an anilox roller, is to apply the proper amount of adhesive 40 onthe printing die 132. Accordingly, the transfer roller 120 includes asurface 124, which may be engraved with a plurality of small cells 122that accept the adhesive 40 from the metering roller 110. Alternatively,the transfer roller 120 need not include the cells 122 and may insteadtransfer the adhesive 40 to the printing die 132 directly from thesurface 124. The cells 122 may be engraved mechanically or by laser toform a plurality of volumes into the surface 124 of the transfer roller120. The cells 122 may be have a variety of shapes known in the art,including trihelical, pyramid, quadrangular, hexagonal, or hexagonalchannel screen. Several characteristics of the transfer roller 120determine the amount of adhesive 40 that will be transferred to theprinting die 132, such as the angle, volume, and line screen density ofthe cells 122. In an exemplary embodiment of the present disclosure, thetransfer roller 120 has a cell line screen density between 100-300 linesper linear inch (LPI) and typically 200 LPI. Typically, lower cellvolumes transfer less adhesive. Conversely, low line screen density willallow for a heavy layer of adhesive 40 to be transferred, whereas highline screen density will permit finer detail in adhesive application. Asis known in the printing art, cell volume and line screen density areclosely correlated. Accordingly, one skilled in the art having thebenefit of this disclosure may recognize that other combinations of cellvolume and line screen density may perform equally well in the adhesiveapplication apparatus 100.

The metering roller 110 may be constructed of a shaft or core of metalor other hard material covered with an elastomeric covering. Theelastomeric covering may be made of neoprene, Buna N (a copolymer ofbutadiene and acrylonitrile), ethylene propylene diene monomer (EPDM),polyurethane, natural rubber, or other suitable material. The transferroller 120 may be constructed of a shaft or core of metal or other hardmaterial covered with a hard, engravable material, such as ceramic,stainless steel, or chrome-plated nickel/copper alloy.

As shown in FIG. 7, the die roller 130 is positioned adjacent to andconfigured to rotate in the opposite direction from the transfer roller120. A printing die 132 is mounted on the die roller 130 such that it isproud of the surface 124 of the die roller 130 and aligned to contactthe transfer roller 120. The rotation of the transfer roller 120 and thedie roller 130 may be closely timed to enable the printing die 132 tocontact the cells 122 on the transfer roller 120. For clarity FIG. 9depicts the transfer roller 120 separated at a distance from the dieroller 130; however, in at least one embodiment the transfer roller 120may contact the die roller 130. As depicted in FIG. 9, as the surface ofthe printing die 132 contacts the cells 122, the adhesive 40 temporarilyadheres to the printing die 132 due to the surface energy of theprinting die 132, thereby transferring a controlled amount of theadhesive 40 from the cells 122 to the printing die 132. The printing die132 is essentially a relief plate made of a flexible and resilientmaterial capable of transferring the adhesive 40 from the cells 122 tothe housing 20, including natural rubber, synthetic elastomeric polymer,and photopolymer that crosslinks upon exposure to ultraviolet energy. Asdepicted in FIG. 9, the contact surface 136 of the printing die 132 maybe course and porous to facilitate acceptance of the adhesive 40 fromthe cells 122 of the transfer roll 120 and subsequent deposition on thehousing 20. Alternatively, the transfer roller 120 need not include thecells 122 and may instead transfer the adhesive 40 to the printing die132 directly from the surface 124.

As shown in FIG. 7, the impression roller 140 is positioned adjacent toand configured to rotate in the opposite direction from the die roller130. In operation, as the die roller 130 rotates, a housing 20 is fedbetween the impression roller 140 and the die roller 130 such that theprinting die 132 contacts the housing 20 and applies the adhesive 40 tothe upper and lower adhesive regions 42, 43 of the housing 20. Thepurpose of the impression roller 140 is to support and apply pressure tothe exterior surface 23 of the housing 20 as the printing die 132contacts the interior surface 25. The impression roller 140 also assiststo feed the housing 20 across the printing die 132. Accordingly, theimpression roller 140 may be made of any suitable material that iscapable to supporting the housing 20 with sufficient pressure to enableadequate transfer of the adhesive 40 from the printing die 132 to thehousing 20 and to feed the housing 20 across the printing die 132.

The die roller 130 may have a plurality of printing dies 132 moundedthereon to enable the application of adhesive 40 onto multiple housings20 with each rotation of the die roller 130. FIG. 6 shows an example ofa housing web 200 for use with the adhesive application apparatus 100.The housing web 200 may comprise three adjacent, uncut housings 20, butthose of ordinary skill in the art will understand that housing websused with the present invention can comprise any number of housings. Byway of example, where the housing web 200 is processed through theadhesive application apparatus 100 of the present disclosure, the dieroller 130 may be configured with a grouping of six printing dies 132corresponding to the upper and lower adhesive regions 42, 43 of eachindividual housing 20 within the housing web 200.

In addition to the die roller 130 and the impression roller 140, theadhesive application apparatus 100 includes a plurality of feed rollers160 that further assist to convey the housing 20 or housing web 200through the apparatus.

As shown in FIG. 8, the adhesive 40 is dispensed into the nip 158 by anadhesive dispense system 150, which controls the flow rate of theadhesive 40 and avoids inducing shear stress in adhesive 40 that maycause the adhesive 40 to congeal and clog the application apparatus 100.The adhesive dispense system 150 may also include a pump 156 fluidlyconnected to a supply line 157 that is further fluidly connected to adispense nozzle 155. The pump 156 may deliver adhesive 40 via the supplyline 157 to the dispense nozzle 155, which dispenses adhesive 40 intothe nip 158. As noted herein, the adhesive 40 is sensitive to shear andmust be delivered to the nip 158 without creating significant shearstress in the adhesive 40. Consequently, the pump 156 may be anon-shearing pump such as a diaphragm pump or a peristaltic pump.

As shown in FIG. 10, according to one embodiment of the presentdisclosure, the pump 156 may be a 360-degree peristaltic pump 500 thatincludes a single pump roller 510 rotatably attached to an eccentricshaft 520. The pump roller 510 compresses a low friction hose 530through 360 degrees of rotation. The benefits of the peristaltic pump500 include more adhesive flow per revolution with only one compressionand expansion per cycle, which reduces shear stress in the adhesive 40.To further reduce shear stress, the pump roller 510 may be configured tominimize the occlusion of the hose 530, which also contributes to inlonger pump life. In at least one embodiment of the pump 156, theocclusion may be between 90-98%. Moreover, the peristaltic pump 500 iscapable of delivering long, steady streams of adhesive 40, which enablesthe pump 500 run relatively slowly and contributes to in longer pumplife while also minimizing shear stress in the adhesive 40.Alternatively, the pump 156 may be a low shearing diaphragm or dualdiaphragm pump well-known in the art.

Shear stress is also a concern at each axial end of the metering 110 andtransfer 120 rollers. To prevent an excessive amount of adhesive 40 fromflowing out of the nip 158 and off the ends of the rollers 110, 120, adam 152 may be placed at each end of the rollers 110, 120, as shown inFIG. 8. However, shear stress may develop in the adhesive 40 between thedam 152 and the ends of the rotating metering and transfer rollers 110,120. To prevent the aforementioned undesirable shearing stress in theadhesive 40, the dams 152 may be allowed to float relative to the endsof the metering 110 and transfer 120 rollers. Nonetheless, some shearstress may be inevitable. Consequently, one or more screen filters 151may be placed adjacent each dam 152, whereby any adhesive 40 that hasbegun to congeal due to shear stress can be removed from the adhesiveflow as the adhesive 40 runs off the axial ends of the metering 110 andtransfer 120 rollers and passed the dams 152. Further, at least onetrough 153 may be located adjacent the screen filters 151 to collectexcess run-off adhesive 40 that passes through the screen filters 151.The trough 153 may be fluidly connected to the pump 156 by arecirculation line 154 to reclaim and reuse excess run-off of adhesive40 from the nip 158, thus minimizing waste and further improving theefficiency of the adhesive application method 800.

Referring to FIG. 8, after passing between die roller 130 and impressionroller 140, the housing 20 may be conveyed passed one or more dryers 170by the plurality of feed rollers 160. The dryers 170 act to evaporatethe remaining liquid from the adhesive 40 applied to the interiorsurface 25 of housing 20, such that the surface tension of the driedadhesive 40 has essentially no tack. Accordingly, the dryers 170 may beany suitable energy source capable to drying the adhesive 40 within therequired line rate of the adhesive application process, includinginfrared or macro-wave lamps, convection ovens, or the like. Because theadhesive application method. 800 applies a very controlled and thinlayer of adhesive 40 isolated to the segregated adhesive regions 42, 43,the adhesive 40 dries to having essentially no tack very quickly, asmuch as 10 times faster than conventional flow or roller coat processes.

The drying of adhesive 40 may be the rate limiting step of the adhesiveapplication method 800, meaning that faster drying methods increase theoverall rate of production of the adhesive application method 800. Forexample, where radio or macro-wave dryers are used and given a housing20 approximately 19 inches long, the adhesive application method 800 mayproduce 5000-6000 coated housings per hour continuously. Where infrareddryers are used 3000-4000 coated and similarly-sized housings per hourmay be produced continuously. In addition, these throughput rates may befurther increased by processing a plurality of housings 20 in the samepass using the housing web 200. Therefore, where the housing web 200includes three adjacent housings 20, as shown in FIG. 6, the productionrates may be as much as three times greater than disclosed.

In at least one embodiment of an adhesive application method 800 of thepresent disclosure, as shown in FIG. 8, the plurality of feed rollers160 may convey the housing 20 through a die punch 180 capable of formingone or more openings 36 through the housing 20. It should be noted thatthe housing 20 may be fed through die punch 180 before or afterapplication of adhesive 40, unlike conventional packaging adhesiveprocesses that must perform the die punch process prior to applicationof the adhesive.

FIG. 19 shows an alternative apparatus for applying the adhesive forproduct packaging according to the present disclosure. As shown in FIG.19, an adhesive application apparatus 300 is similar to the adhesiveapplication apparatus 100; however, the apparatus 300 embodies a numberof significant differences. For instance, instead of a metering roll,such as the metering roll 110 of the apparatus 100, the apparatus 300may include a chambered doctor blade 310. Accordingly, the apparatus 300may include a set of cylindrical rollers 302, including the chambereddoctor blade 310 disposed adjacent a transfer roller 320 with a dieroller 330 adjacent the transfer roller 320. The set of cylindricalrollers 302 may further include an impression roller 340 positionedadjacent the die roller 330 and separated at a distance that permits thehousing 20 to pass therebetween, thus enabling a printing die 332mounted to the die roller 330 to contact the interior surface 25 andimprint the adhesive 40 within the perimeter adhesive regions 42, 43while the impression roller 340 contacts and supports the exteriorsurface 23.

The chambered doctor blade assembly 310 enables precise metering andapplication of the adhesive 40 onto the transfer roll 320. The chambereddoctor blade assembly 310 may include an upper blade 311 a and a lowerblade 311 b mounted to a chamber 314 such that the tips of the upperblade 311 a and the lower blade 311 b contact the transfer roller 320and define a closed nip volume 312. The chamber 314 may include an inlet355 for delivery of the adhesive 40 into the nip volume 312 and anoutlet 353 for draining excess adhesive 40. In operation, the upperblade 311 a and lower blade 311 b may be positioned such that a pool ofadhesive 40, commonly referred to as a nip 358, forms within the nipvolume 312 and contacts the transfer 320 roller. The nip 358 is formedby adhesive 40 supplied via the inlet 355. The upper blade 311 a andlower blade 311 b are further positioned such that a sufficient, but notexcessive, amount of adhesive 40 is transferred to the transfer roll 320in a controlled manner. Excess adhesive 40 may be drained away from thenip volume 312 via the outlet 353. The upper blade 311 a and lower blade311 b may be formed from conventional materials, such as fiberglass,acetal, metal, polyethylene, ultra-high-molecular-weight polyethylene(“UHMWPE”), or any suitable material. The shape of the tips of the upperblade 311 a and lower blade 311 b may be straight, beveled, or beveledwith a step. A UHMWPE blade with a beveled step tip, commonly referredto as a DACC blade, enables a thicker coverage of adhesive 40transferred to the housing 20. In at least one embodiment according tothe present disclosure, the blades 311 a and 311 b may be DACC blades.

Because the chambered doctor blade assembly 310 provides a closed systemfor dispensing and metering the adhesive 40 upon the transfer roller320, some of the dispense and recirculation components of adhesiveapplication apparatus 100 that enable the reuse of excess adhesive 40may not be required in the adhesive application apparatus 300. Forinstance, the adhesive application apparatus 300 may not include dams,filter screens, or a trough. However, as shown in FIG. 20, the adhesiveapplication apparatus 300 may include a supply line 357 fluidlyconnected to a pump 356 at one end and the inlet 355 at the oppositeend. The adhesive application apparatus 300 may further includerecirculation line 354 fluidly connected to the pump 356 at one end andthe outlet 353 at the opposite end. The pump 356 may be substantiallysimilar to the pump 156. Additionally, as a closed system the chambereddoctor blade assembly 310 minimizes induced shear in the adhesive 40and, thereby, potential waste from agglomeration.

The adhesive application apparatus 300 may further differ from theadhesive application apparatus 100 with respect to transfer roller 320.The use of the chambered doctor blade assembly 310 is further enabled bythe transfer roller 320, which may be commonly referred to as an aniloxroller. For clarity FIG. 21 depicts the transfer roller 320 separated ata distance from the die roller 330; however, in at least one embodimentthe transfer roller 320 may contact the die roller 330. As shown in FIG.21, the transfer roller 320 may include a surface 324 having a pluralityof small cells 322 engraved therein. The cells 322 may be similar instructure to the cells 122 of the transfer roller 120 except that theinternal volume 323 of each of the cells 322 is larger than the volumesof the cells 122. In the printing art, the internal volume of cellsengraved in an anilox roller is commonly specified in units of billioncubic microns per square inch (BCM). Larger BCM values equate to greaterinternal cell volumes and result in larger amounts of adhesive 40 beingtransferred from the transfer roller 320 to the print die 332 mounted tothe die roller 330. In an exemplary embodiment of the presentdisclosure, the transfer roller 320 has cell volumes 323 of 40 BCM at aline screen density between 50-100 LPI and typically 60 LPI. However,one skilled in the art having the benefit of this disclosure mayrecognize that other combinations of cell volume and line screen densitymay perform equally well in the adhesive application apparatus 300.Alternatively, the transfer roller 320 need not include the cells 322and may instead transfer the adhesive 40 to the printing die 332directly from the surface 324.

In at least one embodiment of the present disclosure, the adhesive 40may be applied to the interior surface 25 of the housing 20 by anadhesive application method 700. As shown FIG. 17, the adhesiveapplication method 700 includes a step 710 of delivering the adhesive 40to the nip 158 between the rotating metering roller 110 and the adjacentrotating transfer roller 120, the transfer roller 120 having a patternof cells 122 engraved into the transfer roller surface 124, the cells122 being capable of accepting a quantity of the adhesive 40 from thenip 158. The adhesive application method 700 further includes the step720 of rotating the transfer roller 120 whereby the cells 122 contactthe printing die 132 mounted to the rotating die roller 130 positionedadjacent the transfer roller 120, whereby further the adhesive 40 istransferred from the cells 122 to the printing die 132. Moreover, theadhesive application method 700 includes the step 730 of feeding thehousing 20 between the die roller 130 and the adjacent impression roller140, wherein housing 20 includes interior surface 25, opposing exteriorsurface 23, top portion 27, bottom portion 29, top adhesive region 42,bottom adhesive region 43, and is capable of a folded configurationwhereby the interior surfaces 25 of top portion 27 and bottom portion 29at least partially contact each other, and wherein the die roller 130and the impression roller 140 are capable of supporting the exteriorsurface 23 of housing 20. Furthermore, the adhesive application method700 includes the step 740 of rotating the die roller 130 whereby theprinting die 132 contacts top adhesive region 42 and bottom adhesiveregion 43 and thereby transfers the adhesive 40 from the printing die132 to top adhesive region 42 and bottom adhesive region 43 as housing20 advances between the die roller 130 and the impression roller 140.The adhesive application method 700 further includes the step 750 ofrapidly drying the adhesive 40 on housing 20, wherein the adhesive 40 isa latex-based adhesive, with a viscosity of no more than 450 cP, whichadheres to the housing 20 when applied in liquid form but is capable ofdrying such that the dried adhesive 40 lacks tackiness and which is onlycohesive to itself when compressed with a pressure of at least 10,000psi. Alternatively, the transfer roller 120 need not include the cells122 and may instead transfer the adhesive 40 to the printing die 132directly from the surface 124.

In an alternative embodiment of the present disclosure, the adhesive 40may be applied to the interior surface 25 of the housing 20 by anadhesive application method 800. As shown FIG. 22, the adhesiveapplication method 800 includes a step 810 of delivering the adhesive 40to the nip volume 358 within the chambered doctor blade assembly 310 andthe adjacent rotating transfer roller 320, the transfer roller 320having a pattern of cells 322 engraved into the transfer roller surface324, the cells 322 being capable of accepting a quantity of the adhesive40 from the nip volume 358. The adhesive application method 800 furtherincludes the step 820 of rotating the transfer roller 320 whereby thecells 322 contact the printing die 332 mounted to the rotating dieroller 330 positioned adjacent the transfer roller 320, whereby furtherthe adhesive 40 is transferred from the cells 322 to the printing die332. Moreover, the adhesive application method 800 includes the step 830of feeding the housing 20 between the die roller 330 and the adjacentimpression roller 340, wherein housing 20 includes interior surface 25,opposing exterior surface 23, top portion 27, bottom portion 29, topadhesive region 42, bottom adhesive region 43, and is capable of afolded configuration whereby the interior surfaces 25 of top portion 27and bottom portion 29 at least partially contact each other, and whereinthe die roller 330 and the impression roller 340 are capable ofsupporting the exterior surface 23 of housing 20. Furthermore, theadhesive application method 800 includes the step 840 of rotating thedie roller 330 whereby the printing die 332 contacts top adhesive region42 and bottom adhesive region 43 and thereby transfers the adhesive 40from the printing die 332 to top adhesive region 42 and bottom adhesiveregion 43 as housing 20 advances between the die roller 130 and theimpression roller 340. The adhesive application method 800 furtherincludes the step 850 of rapidly drying the adhesive 40 on housing 20,wherein the adhesive 40 is a latex-based adhesive, with a viscosity ofno more than 450 cP, which adheres to the housing 20 when applied inliquid form but is capable of drying such that the dried adhesive 40lacks tackiness and which is only cohesive to itself when compressedwith a pressure of at least 10,000 psi. Alternatively, the transferroller 320 need not include the cells 322 and may instead transfer theadhesive 40 to the printing die 332 directly from the surface 324.

Once the adhesive 40 has been applied and dried on the housing 20, thehousing 20 may be combined with the tray 30 and the product to bepackaged to form the container 10, as shown in FIG. 1. Specifically, atray 30 may be place within the opening 36 in housing 20. Subsequently,the housing 20 may be folded into the folded configuration and sealed.Because of the unique formulation of the adhesive 40, the process forsealing the top portion 27 to the bottom portion 29 of the housing 20differs from conventional contact or cohesive adhesive sealing processesin that high pressure must be applied to the top and bottom portions 27,29 to initiate an adequate bond within the adhesive 40. Specifically,the cohesive characteristics of the adhesive 40 are not highly pressuresensitive, meaning significant pressure must be applied to the substrateto be bound to initiate cohesion of the adhesive 40. As a result, theadhesive 40 has essentially no tack, to itself or uncoated surfaces orsubstrates, under common handling and processing conditions, whichenables efficient shipping and handling of the finished product asdisclosed herein. Further, due to the reduced pressure sensitivity andthin film thickness of the cold seal adhesive 40, conventional productpackaging sealing processes used for conventional cohesive adhesives arenot adequate to create a satisfactory bond between two surfaces coatedwith the cold seal adhesive. Consequently, to produce a satisfactorycohesive bond between two surfaces coated with the cold seal adhesive40, a sealing pressure of more than 10,000 pounds per square inch (psi),and typically about 19,000 psi, must be applied to the surfaces to besealed.

In at least one embodiment of the present disclosure, the housing 20produced by the adhesive application method 800 may be sealed in thefolded configuration by a cold seal compressor method 900 to meet thespecific sealing requirements of the adhesive 40. As shown in FIG. 18,the cold seal compressor method 900 includes the step 910 of folding ahousing 20 having an adhesive 40 applied thereon into the foldedconfiguration; wherein housing 20 comprises interior surface 25,opposing exterior surface 23, top portion 27, bottom portion 29, and topadhesive region 42 and bottom adhesive region 43 on the interior surface25; the folded configuration includes at least partial contact betweenthe interior surfaces 25 of the top portion 27 and bottom portion 29;the adhesive 40 lies within the top adhesive region 42 and bottomadhesive region 43 of the housing 20; and the adhesive 40 comprises alatex-based adhesive, with a viscosity of no more than 450 cP, whichadheres to the housing 40 when applied in liquid form but is capable ofdrying such that the dried adhesive 40 lacks tackiness and which is onlycohesive to itself when compressed with a pressure of at least 10,000psi. The cold seal compressor method 900 further includes the step 920of applying at least 10,000 psi of pressure to the exterior surface 23of the housing 20 opposite the top adhesive region 42 and bottomadhesive region 43 when the housing 20 is in the folded configuration.

FIG. 11 shows a cold seal compressor 600 according to the presentdisclosure for use with the cold seal compressor method 900 to meet thespecific sealing requirements of the adhesive 40. As shown in FIGS. 11and 12, the cold seal compressor 600 includes abed 610 upon which aremounted a plurality of sealing roller pairs 630, 632, 634, 636, 638 thatare mechanically connected to a drive spline 622 that is furthermechanically coupled to a drive motor 620, whereby the drive motor 620powers rotation of the drive spline 622. As shown in FIGS. 11 and 12,the cold seal compressor 600 may include a first sealing roller pair630, a second sealing roller pair 632, a third sealing roller pair 634,and a fourth sealing roller pair 636. Optionally, the cold sealcompressor 600 may include a side sealing roller pair 638 capable ofsealing one edge of the housing 20 with each pass. Each sealing rollerpair is capable of applying a sealing pressure between 10,000 and 40,000psi.

As shown in FIG. 13, each sealing roller pair may include an uppersealing roller 640 and an opposing lower sealing roller 641. Each uppersealing roller 640 may be rotatably mounted on an upper roller shaft 644that is supported by an upper bearing 648 disposed adjacent the uppersealing roller 640. The upper roller shaft 644 is driven by an uppergear 624 disposed on the upper roller shaft 644 adjacent the upperbearing 648. Each lower sealing roller 641 may be disposed adjacent theupper sealing roller 640 and may be rotatably mounted on a lower rollershaft 645 that is supported by a lower bearing 649 disposed adjacent thelower sealing roller 641, whereby the lower roller shaft 645 is drivenby a lower gear 625 disposed adjacent the lower bearing 649 on the lowerroller shaft 645. The upper sealing roller 640 and the lower sealingroller 641 contact each other at a pinch point 462. Each upper gear 624is mechanically coupled to each corresponding lower gear 625, which isin turn mechanically coupled to the drive spline 622. Alternatively,each of the upper and lower gears 624, 625 may include additional gearsdisposed adjacent one another to improve torque conversion and minimizeslippage between the upper and lower gears 624, 625 and the drive spline622. In addition, as shown in FIG. 11, each sealing roller pair may becovered by a guard 650 to prevent an operator from inserting a finger,clothing, or other item between the rotating sealing rollers or gears,thereby preventing personal injury.

In operation, when the housing 20 in the folded configuration is fedbetween the upper sealing roller 640 and the lower sealing roller 641,each sealing roller pair is capable of applying sufficient pressure tothe housing 20 to activate the adhesive 40 applied to the interiorsurface 25 and permanently seal the top and bottom portions 27, 29 ofthe housing 20 to one another. For example, each sealing roller pair mayproduce between 10,000 and 40,000 psi of sealing pressure at a pinchpoint 642 where the upper sealing roller 640 and the lower sealingroller 641 contact one another. The sealing force produced by eachsealing roller pair may be adjustable to accommodate process variations,including the thickness of the housing 20, the thickness of the adhesive40, ambient environmental conditions that affect the pressuresensitivity of the adhesive 40 such as temperature and humidity, andother applicable process parameters.

The cold seal compressor 600 provides a number of advantages overconventional packaging sealing machines. For example, the use ofseparate upper and lower roller shafts 644, 645 for each sealing rollerpair 630, 632, 634, 636, 638 and of a remote drive spline 622 enablessealing of large containers 10 with product volumes 38 that project asignificant depth from the plane of the housing 20, unlike conventionalsealing machines that are limited by the radial dimension of the sealingrollers 640, 641. Moreover, the use of separate upper and lower rollershafts 644, 645 and corresponding bearings 648, 649 disposed in closeproximity to each sealing roller 640, 641 enables each sealing rollerpair 630, 632, 634, 636, 638 to apply the same amount of sealing forceto the housing 20, unlike conventional sealing machines where the use ofa common shaft for all rollers allows the common shaft to deflect overthe distance between sealing roller pairs, thereby reducing to sealforce applied.

The cold seal compressor 600 may be capable of sealing at least twoedges of the housing 20 in one pass. As shown in FIG. 11, the first andsecond sealing roller pair 630, 632 may be positioned on the same planeand separated by a distance less than the width between the first andsecond side edges 26, 28 of the housing 20. Likewise, the third andfourth sealing roller pair 634, 636 may be positioned on a plane andseparated by a distance less than the width between the leading andtrailing edges 22, 24 of the housing 20. The first and second sealingroller pair 630, 632 define a first sealing roller set 631, and thethird and fourth sealing roller pair 634, 636 define a second sealingroller set 639. To facilitate alignment of the housing 20 as it is fedinto each of the first and second sealing roller sets 631, 639, one ormore housing guides 614 may be mounted on the bed 610 on the same planeas the pinch point 642.

In at least one embodiment of the present disclosure, the distancebetween each set of roller pairs (i.e., first and second 630, 632; andthird and fourth 634, 636) may be adjustable. As shown in FIG. 11, thesecond sealing roller pair 632 and associated housing guide 614 may bemounted to a first sliding table 633, which is slidably mounted to thebed 610. Similarly, the third sealing roller pair 634 and associatedhousing guide 614 may be mounted to a second sliding table 635, which isslidably mounted to the bed 610. Each of the sliding tables 633, 635 arecapable of movement along the drive spline 622, whereby the lower gears625 associated with each sealing roller pair 623, 634 maintain themechanical coupling with the drive spline 622 and also remaining inalignment with the first and fourth sealing roller pair 630, 638,respectively. Further, the sliding tables 633, 635 may be held in adesired location along the drive spline 622 by one or more table locks612. Accordingly, the sliding tables 633, 635 enable variablepositioning of the second and third sealing roller pair 632, 634, whichin turn enables the cold seal compressor 600 to seal housings 20 ofvarying widths with a quick and easy adjustment of the location of thesliding tables 633, 635.

In an operation to seal a housing 20 using the cold seal compressor 600,the housing 20 may be fed through the first sealing roller set 631 byany appropriate means and then manually rotated and fed by an operatorinto the second sealing roller set 639. Alternatively, the housing 20may be sealed using a cold seal compressor 601, as shown in FIG. 14. Thecold seal compressor 601 is substantially similar to the cold sealcompressor 600 but differs in the orientation of the second sealingroller set 639 and in the means of transport of the housing 20 from thefirst sealing roller set 631 to the second sealing roller set 639. Asshown in FIG. 14, the cold seal compressor 601 may include a firstsealing roller set 631 and a the second sealing roller set 639 mountedon the same plane to abed 618 and oriented at a right angle to oneanother. Consequently, the first sealing roller set 631 may include adrive motor 620 a mechanically coupled a drive spline 622 a as describedherein relative to the cold seal compressor 600. Likewise, the secondsealing roller set 639 may include a separate drive motor 620 bmechanically coupled a drive spline 622 b as described herein relativeto the cold seal compressor 600.

The cold seal compressor 601 may further include a transfer arm 616slidably mounted to a transfer guide 618 disposed between the first andsecond sealing roller sets 631, 639. The transfer arm 616 conveys andfeeds the housing 20 into the second roller set 639 after the housing 20passes through the first roller set 631. In operation, as shown in FIG.14, the housing 20 may be fed by any appropriate means into the firstroller set 631 in the direction of arrow A. Upon exiting the firstroller set 631, the housing 20 may come to rest adjacent housing guide614 b. The transfer arm 616 may then advance in the direction of arrow Balong the transfer guide 618, thereby conveying and feeding the housing20 into the second roller set 639, which is capable of sealing theremaining unsealed edges of the housing 20. Consequently, the cold sealcompressor 601 is capable of sealing the housing 20 with less manualhandling by an operator.

FIGS. 15 and 16 show an alternative cold seal compressor 602 of thepresent disclosure. The cold seal compressor 602 includes an uppersealing drum 660 in contact with a lower sealing drum 661, both capableof rotation about their respective axes. The cold seal compressor 602may further include a upper drum gear 661 disposed adjacent the uppersealing drum 660 and a lower drum gear 663 disposed adjacent the lowersealing drum 662, whereby the upper and lower drum gears 661, 663 aremechanically coupled to one another. The cold seal compressor 602 mayfurther include a drive motor 620 mechanically coupled to a drum drivegear 622, which in turn is mechanically coupled to the upper and lowerdrum gears 661, 663.

As shown in FIG. 16, the upper sealing drum 660 may include an upperdrum opening 670 through an outer shell 672 sized to accept the productvolume portion 38 of a container 10. Likewise, the lower sealing drum661 may include a lower drum opening 671 through an outer shell 673sized to accept the product volume portion 38 of a container 10. Thecold seal compressor 602 is capable of sealing a housing 20 by applyingsuffice compressive force to exterior surface 23 to activate thecohesive properties of adhesive 40. Unlike the sealing rollers of thecold seal compressor 600 and cold seal compressor 601, which areintended to apply significant sealing force across the relatively narrowperimeter area of the housing 20, the upper and lower sealing drums 660,662 of the cold seal compressor 602 are capable of applying significantsealing force across the entire exterior surface 23 of the housing 20.For example, where the housing 20 includes both perimeter adhesiveregions 42, 43 and product adhesive regions 44, 45 as shown in FIG. 3,the upper and lower drum openings 670, 671 may substantially mimic theflange perimeter 35 of the tray 30, thereby applying sealing pressure toall adhesive regions 42, 43, 44, and 45.

Alternatively, the upper and lower drum openings 670, 671 may include arelief pattern capable of contacting predetermined areas across theexterior surface 23. For example, where the housing 20 includes bothperimeter adhesive regions 42, 43 and product adhesive regions 44, 45 asshown in FIG. 3, the upper and lower drum openings 670, 671 may includeareas between the regions 42, 43, 44, 45 that do not contact theexterior surface 25 because sealing force is not required in those areaswithout applied adhesive 40.

While various embodiments of product packing container and adhesiveapplication method for making the same have been described inconsiderable detail herein, the embodiments are merely offered by way ofnon-limiting examples of the disclosure described herein. It willtherefore be understood that various changes and modifications may bemade, and equivalents may be substituted for elements thereof, withoutdeparting from the scope of the disclosure and are intended to encompassany later appended claims. Indeed, this disclosure is not intended to beexhaustive or to limit the scope of the disclosure.

Further, in describing representative embodiments, the disclosure mayhave presented a method and/or process as a particular sequence ofsteps. However, to the extent that the method or process does not relyon the particular order of steps set forth herein, the method or processshould not be limited to the particular sequence of steps described.Other sequences of steps may be possible. Therefore, the particularorder of the steps disclosed herein should not be construed aslimitations of the present disclosure. In addition, disclosure directedto a method and/or process should not be limited to the performance oftheir steps in the order written. Such sequences may be varied and stillremain within the scope of the present disclosure.

We claim:
 1. A method for applying a cold seal adhesive, the methodcomprising the steps of: delivering a cold seal adhesive to a nipbetween a rotating metering roller and an adjacent rotating transferroller having a transfer surface; transferring a quantity of adhesive tothe transfer surface; rotating the transfer roller whereby the transfersurface contacts a printing die mounted to a rotating die rollerdisposed adjacent to the transfer roller, whereby at least a firstportion of the quantity of adhesive is transferred from the transfersurface to the printing die; feeding a housing between the die rollerand an adjacent rotating impression roller, wherein the housingcomprises an interior surface, an opposing exterior surface, a topportion, a bottom portion, and at least one adhesive region on theinterior surface, and wherein the impression roller is capable ofsupporting the exterior surface of the housing, whereby simultaneousrotation of the die roller and the impression roller advances thehousing therebetween; rotating the die roller whereby the printing diecontacts the at least one adhesive region on the interior surface of thehousing and transfers at least a second portion of the quantity ofadhesive from the printing die to the at least one adhesive regionforming a film as the housing advances between the die roller and theimpression roller, the film having a thickness between 0.0015-0.007inches; and drying the adhesive on the housing; wherein the adhesive isa latex-based adhesive, with a viscosity of no more than 450 centipoise,which adheres to the housing when applied in a liquid form but iscapable of drying such that the dried adhesive lacks tackiness and iscohesive only to itself when compressed with a pressure of at least10,000 pounds per square inch.
 2. The method of claim 1, wherein thetransfer roller further comprises a plurality of cells engraved into thetransfer surface of the transfer roller, the cells being capable ofaccepting the quantity of the adhesive from the nip, wherein the cellscontact the printing die mounted to the rotating die roller disposedadjacent to the transfer roller, whereby the adhesive is transferredfrom the cells to the printing die.
 3. The method of claim 1, whereinthe housing is capable of a folded configuration whereby the interiorsurface of the top portion at least partially contacts the interiorsurface of the bottom portion.
 4. The method of claim 3, furthercomprising the steps of: folding the housing having a cold seal adhesiveapplied thereon into a folded configuration; and applying at least10,000 pounds per square inch of pressure to at least a portion of theexterior surface of the housing opposite the adhesive region when thehousing is in the folded configuration.
 5. The method of claim 1,wherein the adhesive is delivered to the nip using a peristaltic pump.6. The method of claim 1, wherein the adhesive is dried on the housingusing one or more dryers and is advanced to the one or more dryers by aplurality of feed rollers.
 7. The method of claim 6, wherein the one ormore dryers is selected from a group consisting of radio-wave dryers,macro-wave dryers, and infrared dryers.